Cooling system for engine aftertreatment system

ABSTRACT

A cooling system for an engine aftertreatment system at least partially located in an engine compartment including a pressurized air source and an air conduit. The pressurized air source is configured to generate a cooling airflow. The air conduit is connected to the pressurized air source. The air conduit is configured to provide the cooling airflow to the engine aftertreatment system.

TECHNICAL FIELD

The present disclosure relates to an engine aftertreatment system, andmore particularly to a system for cooling the engine aftertreatmentsystem.

BACKGROUND

Selective Catalytic Reduction (SCR) systems may be included in an engineaftertreatment system for a power system to remove or reduce nitrousoxide (NOx or NO) emissions coming from an engine. The SCR systems mayinclude the introduction of a reductant, such as urea, to the exhauststream. The engine aftertreatment system includes a reductant line, anda valve located in an engine compartment, which may get overheatedduring the operation of the engine. Thermal management of the reductantmay be needed for proper operation of the SCR system.

In light of the above, there is a need to provide cooling to the engineaftertreatment system and its associated components which are located inthe engine compartment.

U.S. Pat. No. 6,647,971 discloses a cooling system for an exhaust gasrecirculation system including a valve. A motor opens the valve allowinghot fluid exhaust gas to flow into the valve. Cooling fluid continuouslyflows in and is circulated around the valve, reducing the amount of heattransfer from the hot fluid to the other components in the exhaust gasrecirculation system.

SUMMARY OF THE DISCLOSURE

In one aspect, the present disclosure provides a cooling system for anengine aftertreatment system at least partially located in an enginecompartment. The cooling system includes a pressurized air source and anair conduit. The pressurized air source generates a cooling airflow. Theair conduit is connected to the pressurized air source. The air conduitprovides the cooling airflow to the engine aftertreatment system.

In another aspect, the present disclosure provides a method for coolingan engine aftertreatment system at least partially located in an enginecompartment. The method generates a cooling airflow by a pressurized airsource. Subsequently, the method provides the cooling airflow to theengine aftertreatment system by an air conduit connected to thepressurized air source.

Other features and aspects of this disclosure will be apparent from thefollowing description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view of a power system including an engine, andan engine aftertreatment system, according to an aspect of thedisclosure;

FIG. 2 is a diagrammatic view of a power system including an engine, andan engine aftertreatment system, according to another aspect of thedisclosure; and

FIG. 3 is a process flow diagram for a cooling sequence for the engineaftertreatment system.

DETAILED DESCRIPTION

As seen in FIG. 1, a power system 10 includes an engine 12, and anengine aftertreatment system 14 to treat an exhaust stream 13 producedby the engine 12. The engine 12 may include other features which are notshown, for example, but not limited to, a fuel supply system, an airsystem, insulating systems, peripheries, drivetrain components,turbochargers, electronics, sensors and the like. Moreover, the engine12 may be, without any limitation, an internal combustion engine, agasoline or diesel engine, a natural gas engine, and the like. Theengine 12 may further include a number of cylinders arranged in anysuitable configuration, for example, in-line arrangement, “V”arrangement, radial arrangement, or the like. The engine 12 may be usedto power any machine or other device, including on-highway trucks orvehicles, off-highway trucks or machines, earth moving equipment,generators, aerospace applications, locomotive applications, marineapplications, pumps, stationary equipment, or other engine poweredapplications. Based on the application, the size of the engine 12 mayvary without deviating from the scope of the present disclosure.

During operation of the engine 12, the exhaust stream 13 from the engine12 may enter into the engine aftertreatment system 14. In an embodiment,the engine aftertreatment system 14 includes a Selective CatalyticReduction (SCR) system 18, pre-SCR components 16, post-SCR components20, and an exhaust pipe 22. The exhaust stream 13 exits from the engine12 and passes through the pre-SCR components 16, then passes through theSCR system 18, and then passes through the post-SCR components 20 viathe exhaust pipe 22.

The pre-SCR and post-SCR components 16 and 20 may include devices suchas regeneration devices, heat sources, oxidation catalysts, dieseloxidation catalysts (DOCs), diesel particulate filters (DPFs),additional SCR systems, lean NOx traps (LNTs), mufflers, or otherdevices needed to treat the exhaust stream 13 before and after the SCRsystem 18; and before exiting the power system 10. In various otherembodiments, the pre-SCR and post-SCR components 16 and 20 may or maynot be needed.

In an embodiment, the SCR system 18 may include a reductant system 24,mixer 26, and an SCR device 28. The reductant system 24 introduces orsupplies a reductant 30 into the exhaust stream 13. The mixer 26 may beincluded to mix the reductant 30 in the exhaust stream 13 and introducethe mixture to the SCR device 28. The reductant 30 may be urea, ammonia,diesel fuel, other hydrocarbon, or chemical used by the SCR device 28 toreduce or otherwise remove NOx or NO emissions from the exhaust stream13. The SCR device 28 may include a catalyst facilitating the reaction,reduction, or removal of NOx emissions from the exhaust stream 13 as itpasses through the SCR device 28.

Moreover, the reductant system 24 is shown to include a reductant source32, a pump 34, a valve 36, an injector 38, and a reductant line 40. Thereductant source 32 may be a tank, vessel, absorbing material, or otherdevice capable of storing and releasing the reductant 30. The reductantline 40 transports the reductant 30 from the reductant source 32 to theexhaust stream 13 of the engine 12 via the injector 38.

The pump 34 is an extraction device capable of passing the reductant 30from the reductant source 32, generating a reductant flow 31. The valve36 may be included to help regulate or control the delivery of thereductant 30. The injector 38 is a device capable of creating areductant spray or otherwise introducing the reductant 30 in the exhauststream 13. The injector 38 may be designed to introduce the reductant 30in the exhaust stream 13 with or without the aid of compressed air.

As shown in the FIG. 1, the engine 12 and the engine aftertreatmentsystem 14 may be contained or located inside an engine compartment 42.The engine compartment 42 may define an engine compartment interiorspace 44 inside. The engine compartment 42 may be the machine's hood orengine's enclosure. The engine compartment 42 may include vents forventilation and other components (not shown). Components shown to beinside the engine compartment 42 may alternatively be located outsidethe engine compartment 42 and components shown to be outside the enginecompartment 42 may alternatively be located inside the enginecompartment 42. The reductant source 32 may be located outside orotherwise thermally insulated from the engine compartment 42.

In an embodiment of the present disclosure, a cooling system 46 isprovided for the engine aftertreatment system 14. The cooling system 46may include a pressurized air source 48 and an air conduit 50. The airconduit 50 may be connected to the pressurized air source 48. As shownin the FIG. 1, the air conduit 50 may be partially located inside theengine compartment 42; such that the air conduit 50 may surround thereductant line 40.

In an embodiment, the pressurized air source 48 may include a fan 52.The fan 52 may pull in air from ambient environment and generate acooling airflow 54. The fan 52 may be configured to provide the coolingairflow 54 to the engine aftertreatment system 14 through the airconduit 50.

In an embodiment, the pressurized air source 48 may include more thanone fan 52. It will be apparent to a person skilled in the art that thefan 52 may include an axial fan configured to pull the ambient airthrough inlet vents 56 provided in the cooling system 46. Further, oneor more outlet vents 58 may be provided to move the generated coolingairflow 54 at very high speed. Moreover, the cooling system 46 mayinclude a wire mesh filter to keep the dust and foreign particulateoutside the cooling system 46.

In another embodiment of the present disclosure, the cooling system 46may be coupled to a heat exchanging system 60. As shown in the FIG. 2,the heat exchanging system 60 may embody another cooling systemassociated with the engine 12, or may embody another heat exchangingsystem in the power system 10. Further, the heat exchanging system 60,as shown, may include a radiator 62, radiator inlet line 64, andradiator outlet line 66.

In an embodiment, the fan 52 may also be used to provide the coolingairflow 54 to the radiator 62. Moreover, the fan 52 may either belocated within or outside the engine compartment 42, without deviatingfrom the scope of the disclosure.

FIG. 3 is a process flow diagram of a cooling sequence 300 for theengine aftertreatment system 14. At step 302, the pressurized air source48 generates the cooling airflow 54.

Further, at step 304 the cooling airflow 54 is provided to the engineaftertreatment system 14 by the air conduit 50. The air conduit 50 isconnected to the pressurized air source 48.

In one embodiment, the cooling airflow 54 may be provided to thereductant line 40 of the engine aftertreatment system 14, by the airconduit 50 that surrounds the reductant line 40. Hence, the coolingairflow 54 may be used to cool the reductant 30 flowing through thereductant line 40. In another embodiment, the cooling airflow 54 may beprovided to the valve 36 which is located on the reductant line 40.Hence, the cooling airflow 54 may also facilitate in cooling the valve36.

INDUSTRIAL APPLICABILITY

During operation of the engine 12, a large amount of heat may begenerated. This may lead to an increase in temperature within the enginecompartment 42. The rise in temperature may correspondingly causecomponents located within the engine compartment interior space 44 toget overheated. For example, the valve 36 and the reductant line 40 maybe overheated due to high temperatures in the engine compartment 42,causing the reductant 30 in the reductant line 40 to get heated. As aresult, the reductant 30 may not be able to effectively absorb thediesel particulate emission in the engine aftertreatment system 14.

Typical solutions use a combination of techniques such as, but notlimited to shielding, deflecting, and/or forced ventilation to cool thecomponents within the engine compartment 42. However, these coolingmethods did not meet the exact cooling need or reduce heat transfer fromthe hot environment in the engine compartment interior space 44 to thereductant 30 being delivered by the reductant line 40.

The cooling system 46 described above provides the cooling airflow 54generated by the pressurized air source 48 to the air conduit 50, inorder to cool the reductant line 40. The cooling system 46 may alsofacilitate in cooling of the valve 36 associated with the reductant line40. In one embodiment, a simple nested assembly of the air conduit 50,wherein the air conduit 50 may be attached at one end to the pressurizedair source 48, and connected at another end to the valve 36; mayfacilitate in effectively cooling the reductant line 40 as well as thevalve 36.

Moreover, as described earlier, the pressurized air source 48 mayinclude the fan 52. In one embodiment, the fan 52 may also be used toprovide the cooling airflow 54 to the engine 12. Hence, by using thesame fan 52 to cool the engine 12 and the reductant line 40, the use ofan additional separate fan assembly may be avoided. By cutting down onthe use of the additional separate fan assembly, complexity and cost ofthe same may be saved by using the cooling system 46.

Additionally, when the fan 52 is located outside the engine compartment42, walls of the engine compartment 42 may act as a bulkhead between thefan 52 and the components lying within the engine compartment interiorspace 44. This may assist in creating an area of high pressure in orderto facilitate in generating the cooling airflow 54.

A person of ordinary skill in that will appreciate that although the useof the cooling system 46 has been explained in conjunction with coolingof the reductant line 40 of the engine aftertreatment system 14, thecooling system 46 may also be used to cool any other component at leastpartially located within the engine compartment 42, without deviatingfrom the scope and spirit of the disclosure.

While aspects of the present disclosure have been particularly shown anddescribed with reference to the embodiments above, it will be understoodby those skilled in the art that various additional embodiments may becontemplated by the modification of the disclosed machines, systems andmethods without departing from the spirit and scope of what isdisclosed. Such embodiments should be understood to fall within thescope of the present disclosure as determined based upon the claims andany equivalents thereof.

1. A cooling system for an engine aftertreatment system at leastpartially located inside an engine compartment, the system comprising: apressurized air source configured to generate a cooling airflow; and anair conduit connected to the pressurized air source and configured toprovide the cooling airflow to the engine aftertreatment system.
 2. Thecooling system of claim 1, wherein the air conduit is located at leastpartially inside the engine compartment.
 3. The cooling system of claim1, wherein the engine aftertreatment system includes a reductant lineconnected to a reductant source.
 4. The cooling system of claim 3,wherein the air conduit surrounds the reductant line.
 5. The coolingsystem of claim 3, wherein the engine aftertreatment system furtherincludes a valve provided on the reductant line.
 6. The cooling systemof claim 5, wherein the air conduit deliver the cooling airflow to thevalve.
 7. The cooling system of claim 3, wherein the reductant source islocated outside the engine compartment.
 8. The cooling system of claim1, wherein the pressurized air source includes a fan.
 9. A power systemcomprising: an engine contained inside an engine compartment; an engineaftertreatment system associated with the engine; and a cooling systemfor the engine aftertreatment system, the system including: apressurized air source configured to generate a cooling airflow; and anair conduit connected to the pressurized air source and configured toprovide the cooling airflow to the engine aftertreatment system.
 10. Thepower system of claim 9, wherein the air conduit is located at leastpartially inside the engine compartment.
 11. The power system of claim9, wherein the engine aftertreatment system includes a reductant lineconnected to a reductant source.
 12. The power system of claim 11,wherein the air conduit surrounds the reductant line.
 13. The powersystem of claim 11, wherein the engine aftertreatment system furtherincludes a valve provided on the reductant line.
 14. The power system ofclaim 13, wherein the air conduit delivers the cooling airflow to thevalve.
 15. The power system of claim 13, wherein the pressurized airsource delivers the cooling airflow to a radiator associated with theengine.
 16. A method for cooling an engine aftertreatment system atleast partially located inside an engine compartment, the methodcomprising: generating a cooling airflow by a pressurized air source;and providing the cooling airflow to the engine aftertreatment system byan air conduit connected to the pressurized air source.
 17. The methodof claim 16, wherein the cooling airflow is further provided to areductant line.
 18. The method of claim 17, wherein the cooling airflowis further provided to a valve connected to the reductant line.